Smoke Continued to be the Story Last Weekend at DISCOVER-AQ Platteville-Colorado Site

Canadian wildfires and fires in the Pacific Northwest effected much of the northern US last week, making the air in northern half smoky, hazy, and even having unhealthy AQI (Air Quality Index) levels of PM 2.5. AIRS NRT observations in the mid-troposphere (~5.5-6.5km) places a layer of smoke above the DISCOVER-AQ Platteville site on the afternoon of 19th of July (last Saturday). Elevated concentrations of ozone and CO (carbon monoxide) correlate with intensely dry air in this layer high above northern Colorado.  NOAA HMS Smoke and Fire Product on the 17th and 18th of July (shown in previous blog post) indicate a main smoke plume originating from fires in western Canada and northwestern US.  Additional HYSPLIT trajectories (not shown but verbal communication with Ryan Stauffer) suggests the source to be smoke coming from Canadian fires. 

AIRS Day NRT ozone (top left), CO (top right), and relative humidity (bottom left) at 500mb (~5.5-6.5km) via Debra Kollonige of ESSIC/UMD.

Ozonesondes launched at Platteville show the progression of the smoke layer in the upper levels at 6-9km (on the 17th, 18th, and 19th) to its descent and dissipation at 5-7km (on the 20th and 21st) above the surface.  The highest concentrations of ozone measured by the sonde are on the 17th (afternoon-left top below) as the smoke plume begins to enter the site area at 8km (~350mb) and the 20th (morning) at 7km (~400mb) before the air mass descends (bottom right below) and mixes into lower levels on the 21st. [See PSU Gator Ozonesonde Quicklooks for additional days.]

Ozonesonde profiles launched at DISCOVER-AQ Platteville-Colorado site July 16-21 courtesy of Ryan Stauffer of PSU.

AIRS Day NRT trace gas measurements averaged over the Platteville area (retrievals within 50km)  indicate the entrance of a smoke layer over Platteville by the 17th with dry, ozone and CO rich air in the upper levels.  Peaking on the 19th, AIRS missed the higher concentration measured by the sonde on the 17th because of the course vertical resolution of the observations.  Still, its time series of ozone, CO, and relative humidity between 5 and 9km shows the buildup of ozone and CO over Platteville 17-19 July, descent of the smoke/polluted air mass starting on the 20th, and its mixing/dissipation into the lower levels on the 21st.  [See the UMBC Smog Blog at http://alg.umbc.edu/usaq/ for additional images of the descent of the smoke layer towards the surface via lidar measurements posted on July 19/20.]

AIRS Day NRT series of trace gases (ozone, relative humidity, CO and methane respectively top to bottom) observed July 16-22 at several levels including 500mb (black), 400mb (red), and 300mb (blue), which range in altitude from 5.5-9km.  Figure courtesy of Debra Kollonige.

Stay tuned for more satellite and DISCOVER-AQ measurements now that the mission has completed a few flights this week.